Gestational trophoblastic disease | |
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Micrograph of intermediate trophoblast, decidua and a hydatidiform mole (bottom of image). H&E stain. | |
Specialty | Oncology |
Gestational trophoblastic disease (GTD) is a term used for a group of pregnancy-related tumours. These tumours are rare, and they appear when cells in the womb start to proliferate uncontrollably. The cells that form gestational trophoblastic tumours are called trophoblasts and come from tissue that grows to form the placenta during pregnancy.
There are several different types of GTD. A hydatidiform mole also known as a molar pregnancy, is the most common and is usually benign. Sometimes it may develop into an invasive mole, or, more rarely into a choriocarcinoma. A choriocarcinoma is likely to spread quickly, [1] [2] but is very sensitive to chemotherapy, and has a very good prognosis. Trophoblasts are of particular interest to cell biologists because, like cancer, they can invade tissue (the uterus), but unlike cancer, they usually "know" when to stop.[ citation needed ]
GTD can simulate pregnancy, because the uterus may contain fetal tissue, albeit abnormal. This tissue may grow at the same rate as a normal pregnancy, and produces chorionic gonadotropin, a hormone which is measured to monitor fetal well-being. [3]
While GTD overwhelmingly affects women of child-bearing age, it may rarely occur in postmenopausal women. [4]
GTD is the common name for five closely related tumours (one benign tumour, and four malignant tumours): [5]
Here, first a fertilised egg implants into the uterus, but some cells around the fetus (the chorionic villi) do not develop properly. The pregnancy is not viable, and the normal pregnancy process turns into a benign tumour. There are two subtypes of hydatidiform mole: complete hydatidiform mole, and partial hydatidiform mole.[ citation needed ]
All five closely related tumours develop in the placenta. All five tumours arise from trophoblast cells that form the outer layer of the blastocyst in the early development of the fetus. In a normal pregnancy, trophoblasts aid the implantation of the fertilised egg into the uterine wall. But in GTD, they develop into tumour cells. [6]
Two main risk factors increase the likelihood for the development of GTD: 1) The woman being under 20 years of age, or over 35 years of age, and 2) previous GTD. [7] [8] [9] Although molar pregnancies affect women of all ages, women under 16 and over 45 years of age have an increased risk of developing a molar pregnancy. [10]
Hydatidiform moles are abnormal conceptions with excessive placental development. Conception takes place, but placental tissue grows very fast, rather than supporting the growth of a fetus. [11] [12] [13]
Complete hydatidiform moles have no fetal tissue and no maternal DNA, as a result of a maternal ovum with no functional DNA. Most commonly, a single spermatozoon duplicates and fertilises an empty ovum. Less commonly, two separate spermatozoa fertilise an empty ovum (dispermic fertilisation). Partial hydatidiform moles have a fetus or fetal cells. They are triploid in origin, containing one set of maternal haploid genes and two sets of paternal haploid genes. They almost always occur following dispermic fertilisation of a normal ovum. Malignant forms of GTD are very rare. About 50% of malignant forms of GTD develop from a hydatidiform mole.[ citation needed ]
Cases of GTD can be diagnosed through routine tests given during pregnancy, such as blood tests and ultrasound, or through tests done after miscarriage or abortion. [14] Vaginal bleeding, enlarged uterus, pelvic pain or discomfort, and vomiting too much (hyperemesis) are the most common symptoms of GTD. But GTD also leads to elevated serum hCG (human chorionic gonadotropin hormone). Since pregnancy is by far the most common cause of elevated serum hCG, clinicians generally first suspect a pregnancy with a complication. However, in GTD, the beta subunit of hCG (beta hCG) is also always elevated. Therefore, if GTD is clinically suspected, serum beta hCG is also measured. [15]
The initial clinical diagnosis of GTD should be confirmed histologically, which can be done after the evacuation of pregnancy (see Treatment below) in women with hydatidiform mole. [16] However, malignant GTD is highly vascular. If malignant GTD is suspected clinically, biopsy is contraindicated, because biopsy may cause life-threatening haemorrhage.
Women with persistent abnormal vaginal bleeding after any pregnancy, and women developing acute respiratory or neurological symptoms after any pregnancy, should also undergo hCG testing, because these may be signs of a hitherto undiagnosed GTD.
There might be some signs and symptoms of hyperthyroidism as well as an increase in the levels of thyroid hormones in some patients. The proposed mechanism is attaching hCG to TSH receptors and acting like TSH weakly. [17]
Both are composed of intermediate trophoblast, but their morphological features and clinical presentation can differ significantly.
Exaggerated placental site is a benign, non cancerous lesion with an increased number of implantation site intermediate trophoblastic cells that infiltrate the endometrium and the underlying myometrium. An exaggerated placental site may occur with normal pregnancy, or after an abortion. No specific treatment or follow up is necessary.
Placental site nodules are lesions of chorionic type intermediate trophoblast, usually small. 40 to 50% of placental site nodules are found in the cervix. They almost always are incidental findings after a surgical procedure. No specific treatment or follow up is necessary.
Treatment is always necessary.[ citation needed ]
The treatment for hydatidiform mole consists of the evacuation of pregnancy. [19] [20] [21] [22] [23] Evacuation will lead to the relief of symptoms, and also prevent later complications. Suction curettage is the preferred method of evacuation. Hysterectomy is an alternative if no further pregnancies are wished for by the female patient. Hydatidiform mole also has successfully been treated with systemic (intravenous) methotrexate. [24]
The treatment for invasive mole or choriocarcinoma generally is the same. Both are usually treated with chemotherapy. Methotrexate and dactinomycin are among the chemotherapy drugs used in GTD. [25] [26] [27] [28] In women with low risk gestational trophoblastic neoplasia, a review has found that Actinomycin D is probably more effective as a treatment and more likely to achieve a cure in the first instance than methotrexate. [29] Only a few women with GTD have poor prognosis metastatic gestational trophoblastic disease. Their treatment usually includes chemotherapy. Radiotherapy can also be given to places where the cancer has spread, e.g. the brain. [30]
Women who undergo chemotherapy are advised not to conceive for one year after completion of treatment. These women also are likely to have an earlier menopause. It has been estimated by the Royal College of Obstetricians and Gynaecologists that the age at menopause for women who receive single agent chemotherapy is advanced by one year, and by three years for women who receive multi agent chemotherapy.[ citation needed ]
Follow up is necessary in all women with gestational trophoblastic disease, because of the possibility of persistent disease, or because of the risk of developing malignant uterine invasion or malignant metastatic disease even after treatment in some women with certain risk factors. [31] [32]
The use of a reliable contraception method is very important during the entire follow up period, as patients are strongly advised against pregnancy at that time. If a reliable contraception method is not used during the follow-up, it could be initially unclear to clinicians as to whether a rising hCG level is caused by the patient becoming pregnant again, or by the continued presence of GTD.[ citation needed ]
In women who have a malignant form of GTD, hCG concentrations stay the same (plateau) or they rise. Persistent elevation of serum hCG levels after a non molar pregnancy (i.e., normal pregnancy [term pregnancy], or preterm pregnancy, or ectopic pregnancy [pregnancy taking place in the wrong place, usually in the fallopian tube], or abortion) always indicate persistent GTD (very frequently due to choriocarcinoma or placental site trophoblastic tumour), but this is not common, because treatment mostly is successful.
In rare cases, a previous GTD may be reactivated after a subsequent pregnancy, even after several years. Therefore, the hCG tests should be performed also after any subsequent pregnancy in all women who had had a previous GTD (6 and 10 weeks after the end of any subsequent pregnancy).
Women with a hydatidiform mole have an excellent prognosis. Women with a malignant form of GTD usually have a very good prognosis. [33]
Choriocarcinoma, for example, is an uncommon, yet almost always curable cancer. Although choriocarcinoma is a highly malignant tumour and a life-threatening disease, it is very sensitive to chemotherapy. Virtually all women with non-metastatic disease are cured and retain their fertility; the prognosis is also very good for those with metastatic (spreading) cancer, in the early stages, but fertility may be lost. Hysterectomy (surgical removal of the uterus) can also be offered [34] to patients > 40 years of age or those for whom sterilisation is not an obstacle. Only a few women with GTD have a poor prognosis, e.g. some forms of stage IV GTN. The FIGO staging system is used. [35] The risk can be estimated by scoring systems such as the Modified WHO Prognostic Scoring System, wherein scores between 1 and 4 from various parameters are summed together: [36]
0 | 1 | 2 | 4 | |
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Age | <40 | ≥40 | – | – |
Antecedent pregnancy | mole | abortion | term | – |
Interval months from index pregnancy | <4 | 4–6 | 7–12 | >12 |
Pretreatment serum hCG (IU/L) | <103 | 103–104 | 104–105 | >105 |
Largest tumor size (including uterus) | <3 | 3–4 cm | ≥5 cm | – |
Site of metastases | lung | spleen, kidney | gastrointestinal | liver, brain |
Number of metastases | – | 1–4 | 5–8 | >8 |
Previous failed chemotherapy | – | – | single drug | ≥2 drugs |
In this scoring system, women with a score of 7 or greater are considered at high risk.
It is very important for malignant forms of GTD to be discovered in time. In Western countries, women with molar pregnancies are followed carefully; for instance, in the UK, all women who have had a molar pregnancy are registered at the National Trophoblastic Screening Centre. [37] There are efforts in this direction in the developing countries too, and there have been improvements in these countries in the early detection of choriocarcinoma, thereby significantly reducing the mortality rate also in developing countries. [38] [39] [40]
Most women with GTD can become pregnant again and can have children again. The risk of a further molar pregnancy is low. More than 98% of women who become pregnant following a molar pregnancy will not have a further hydatidiform mole or be at increased risk of complications.[ citation needed ]
In the past, it was seen as important not to get pregnant straight away after a GTD. Specialists recommended a waiting period of six months after the hCG levels become normal. Recently, this standpoint has been questioned. New medical data suggest that a significantly shorter waiting period after the hCG levels become normal is reasonable for approximately 97% of the patients with hydatidiform mole. [41]
The risk of a repeat GTD is approximately 1 in 100, compared with approximately 1 in 1000 risk in the general population. Especially women whose hCG levels remain significantly elevated are at risk of developing a repeat GTD. [42]
The term «persistent trophoblastic disease» (PTD) is used when after treatment of a molar pregnancy, some molar tissue is left behind and again starts growing into a tumour. Although PTD can spread within the body like a malignant cancer, the overall cure rate is nearly 100%. [43]
In the vast majority of patients, treatment of PTD consist of chemotherapy. Only about 10% of patients with PTD can be treated successfully with a second curettage. [44] [45]
In some very rare cases, a GTD can coexist with a normal fetus. This is called a "twin pregnancy". These cases should be managed only by experienced clinics, after extensive consultation with the patient. Because successful term delivery might be possible, the pregnancy should be allowed to proceed if the mother wishes, following appropriate counselling. The probability of achieving a healthy baby is approximately 40%, but there is a risk of complications, e.g. pulmonary embolism and pre-eclampsia. Compared with women who simply had a GTD in the past, there is no increased risk of developing persistent GTD after such a twin pregnancy. [46] [47] [48] [49] [50] [51]
In few cases, a GTD had coexisted with a normal pregnancy, but this was discovered only incidentally after a normal birth. [52]
Overall, GTD is a rare disease. Nevertheless, the incidence of GTD varies greatly between different parts of the world. The reported incidence of hydatidiform mole ranges from 23 to 1299 cases per 100,000 pregnancies. The incidence of the malignant forms of GTD is much lower, only about 10% of the incidence of hydatidiform mole. [53] The reported incidence of GTD from Europe and North America is significantly lower than the reported incidence of GTD from Asia and South America. [54] [55] [56] [57] One proposed reason for this great geographical variation is differences in healthy diet in the different parts of the world (e.g., carotene deficiency). [58]
However, the incidence of rare diseases (such as GTD) is difficult to measure, because epidemiologic data on rare diseases is limited. Not all cases will be reported, and some cases will not be recognised. In addition, in GTD, this is especially difficult, because one would need to know all gestational events in the total population. Yet, it seems very likely that the estimated number of births that occur at home or outside of a hospital has been inflated in some reports. [59]
Gestational trophoblastic disease (GTD) may also be called gestational trophoblastic tumour (GTT). Hydatidiform mole (one type of GTD) may also be called molar pregnancy.[ citation needed ]
Persistent disease; persistent GTD: If there is any evidence of persistence of GTD, usually defined as persistent elevation of beta hCG (see «Diagnosis» below), the condition may also be referred to as gestational trophoblastic neoplasia (GTN). [60]
Ectopic pregnancy is a complication of pregnancy in which the embryo attaches outside the uterus. Signs and symptoms classically include abdominal pain and vaginal bleeding, but fewer than 50 percent of affected women have both of these symptoms. The pain may be described as sharp, dull, or crampy. Pain may also spread to the shoulder if bleeding into the abdomen has occurred. Severe bleeding may result in a fast heart rate, fainting, or shock. With very rare exceptions, the fetus is unable to survive.
Human chorionic gonadotropin (hCG) is a hormone for the maternal recognition of pregnancy produced by trophoblast cells that are surrounding a growing embryo, which eventually forms the placenta after implantation. The presence of hCG is detected in some pregnancy tests. Some cancerous tumors produce this hormone; therefore, elevated levels measured when the patient is not pregnant may lead to a cancer diagnosis and, if high enough, paraneoplastic syndromes, however, it is not known whether this production is a contributing cause, or an effect of carcinogenesis. The pituitary analog of hCG, known as luteinizing hormone (LH), is produced in the pituitary gland of males and females of all ages.
An ovarian cyst is a fluid-filled sac within the ovary. Often they cause no symptoms. Occasionally they may produce bloating, lower abdominal pain, or lower back pain. The majority of cysts are harmless. If the cyst either breaks open or causes twisting of the ovary, it may cause severe pain. This may result in vomiting or feeling faint, and even cause head aches.
The trophoblast is the outer layer of cells of the blastocyst. Trophoblasts are present four days after fertilization in humans. They provide nutrients to the embryo and develop into a large part of the placenta. They form during the first stage of pregnancy and are the first cells to differentiate from the fertilized egg to become extraembryonic structures that do not directly contribute to the embryo. After blastulation, the trophoblast is contiguous with the ectoderm of the embryo and is referred to as the trophectoderm. After the first differentiation, the cells in the human embryo lose their totipotency because they can no longer form a trophoblast. They become pluripotent stem cells.
A molar pregnancy, also known as a hydatidiform mole, is an abnormal form of pregnancy in which a non-viable fertilized egg implants in the uterus. It falls under the category of gestational trophoblastic diseases and was previously known as a hydatidiform mole. During a molar pregnancy, the uterus contains a growing mass characterized by swollen chorionic villi, resembling clusters of grapes. The occurrence of a molar pregnancy can be attributed to the fertilized egg lacking an original maternal nucleus. As a result, the products of conception may or may not contain fetal tissue. These molar pregnancies are categorized into two types: partial moles and complete moles, where the term 'mole' simply denotes a clump of growing tissue or a ‘growth'.
Choriocarcinoma is a malignant, trophoblastic cancer, usually of the placenta. It is characterized by early hematogenous spread to the lungs. It belongs to the malignant end of the spectrum in gestational trophoblastic disease (GTD). It is also classified as a germ cell tumor and may arise in the testis or ovary.
Gestational choriocarcinoma is a form of gestational trophoblastic neoplasia, which is a type of gestational trophoblastic disease (GTD), that can occur during pregnancy. It is a rare disease where the trophoblast, a layer of cells surrounding the blastocyst, undergoes abnormal developments, leading to trophoblastic tumors. The choriocarcinoma can metastasize to other organs, including the lungs, kidney, and liver. The amount and degree of choriocarcinoma spread to other parts of the body can vary greatly from person to person.
Placental abruption is when the placenta separates early from the uterus, in other words separates before childbirth. It occurs most commonly around 25 weeks of pregnancy. Symptoms may include vaginal bleeding, lower abdominal pain, and dangerously low blood pressure. Complications for the mother can include disseminated intravascular coagulopathy and kidney failure. Complications for the baby can include fetal distress, low birthweight, preterm delivery, and stillbirth.
Dilation and evacuation (D&E) is the dilation of the cervix and surgical evacuation of the uterus after the first trimester of pregnancy. It is a method of abortion as well as a common procedure used after miscarriage to remove all pregnancy tissue.
Complications of pregnancy are health problems that are related to, or arise during pregnancy. Complications that occur primarily during childbirth are termed obstetric labor complications, and problems that occur primarily after childbirth are termed puerperal disorders. While some complications improve or are fully resolved after pregnancy, some may lead to lasting effects, morbidity, or in the most severe cases, maternal or fetal mortality.
Dactinomycin, also known as actinomycin D, is a chemotherapy medication used to treat a number of types of cancer. This includes Wilms tumor, rhabdomyosarcoma, Ewing's sarcoma, trophoblastic neoplasm, testicular cancer, and certain types of ovarian cancer. It is given by injection into a vein.
Gestational trophoblastic neoplasia (GTN) is group of rare diseases related to pregnancy and included in gestational trophoblastic disease (GTD) in which abnormal trophoblast cells grow in the uterus. GTN can be classified into benign and malignant lesions. Benign lesions include placental site nodule and hydatidiform moles while malignant lesions have four subtypes including invasive mole, gestational choriocarcinoma, placental site trophoblastic tumor (PSTT) and epithelioid trophoblastic tumor (ETT). The choriocarcinoma has 2 significant subtypes including gestational and non-gestational and they are differentiated by their different biological feature and prognosis. Signs and symptoms of GTN will appear vary from person to person and depending upon the type of the disease. They may include uterine bleeding not related to menstruation, pain or pressure in pelvis, large uterus and high blood pressure during pregnancy. The cause of this disease is unknown but the identification of the tumor based on total beta-human chorionic gonadotropin (β-hCG) in the serum.
Invasive hydatidiform mole is a type of neoplasia that grows into the muscular wall of the uterus. It is formed after conception. It may spread to other parts of the body, such as the vagina, vulva, and lung.
A placental disease is any disease, disorder, or pathology of the placenta.
Placental site trophoblastic tumor is a form of gestational trophoblastic disease, which is thought to arise from intermediate trophoblast.
Theca lutein cyst is a type of bilateral functional ovarian cyst filled with clear, straw-colored fluid. These cysts result from exaggerated physiological stimulation due to elevated levels of beta-human chorionic gonadotropin (beta-hCG) or hypersensitivity to beta-hCG. On ultrasound and MRI, theca lutein cysts appear in multiples on ovaries that are enlarged.
Sylvia Dorothy Lawler was an English geneticist who worked in the field of human genetics.
Min Chiu Li was a Chinese-American oncologist and cancer researcher. Li was the first scientist to use chemotherapy to cure widely metastatic, malignant cancer.
Early pregnancy bleeding refers to vaginal bleeding before 14 weeks of gestational age. If the bleeding is significant, hemorrhagic shock may occur. Concern for shock is increased in those who have loss of consciousness, chest pain, shortness of breath, or shoulder pain.
Hypertensive disease of pregnancy, also known as maternal hypertensive disorder, is a group of high blood pressure disorders that include preeclampsia, preeclampsia superimposed on chronic hypertension, gestational hypertension, and chronic hypertension.